Fig. 1. (a) Optical microscope image of the variable aperture OPA. (b) Schematic of the variable aperture OPA. (c) Electrically and optically packaged variable aperture OPA chip with control circuit.

Fig. 2. Schematic diagram of optical path distribution for OPA with (a) 64, (b) 128, (c) 192, and (d) 256 antennas.

Fig. 3. Beam steering performance of (a) 64, (b) 128, (c) 192, and (d) 256 channels at 0°, ±5°, and ±10°; each contains a light spot picture captured by a near-infrared camera and intensity distribution along the cross section of the light spot.

Fig. 4. Main lobe divergence at 0° with different aperture scales.

Fig. 5. (a) Power consumption required for steering under different apertures within the range of −10° to 10°; (b) average power consumption under different apertures.

Fig. 6. Configuring the voltage for (a) 64, (b) 128, (c) 192, and (d) 256 channels at the same time, and the turn-on time of the last channel.

Fig. 7. Far-field distance for different apertures.

Fig. 8. (a) Simulated formation process for light beams of 64-, 128-, 192-, and 256-channel OPA along with distance; (b) captured beam spot at the distance of 3 cm, 10 cm, and 20 cm.

Fig. 9. Schematic diagram of gaze scanning using different apertures.

Fig. 10. Sum of the normalized far-field spot obtained by the (a) 64-channel aperture and (b) 256-channel aperture steering with laser wavelength and phase shift.

Fig. 11. (a) Picture of the letters JLU as a scanning target; (b) full-range scanning using 64-channel aperture; (c) gaze on the letters J, L, and U using 256-channel aperture.

Fig. 12. Schematic diagram of RA-OPA embedded FMCW LiDAR system.

Fig. 13. (a) Picture of experimental setup. RF spectra for the beat signal in the cases of (b) 64-channel, (c) 128-channel, (d) 192-channel, and (e) 256-channel OPA at a distance of 2 m.

Fig. 14. (a) Picture of targets placed in front of the OPA in different directions; (b) experimental result for a rough scan of the target by using 64-channel aperture; (c) experimental result for a fine scan of the target by using 256-channel aperture; (d) gaze at the corner of the target using 256-channel aperture; and (e) target position information obtained by splicing rough scan and gaze areas.